One of the tasks of a mobile communications network is to transport data flows from a network access point towards an application located somewhere in the network. One aspect of this task is how to react if the application becomes overloaded.
An application is a data plane application and examples of data plane applications are policy and enforcement functions, service aware traffic shaping, transcoding, transrating, media caching, packet inspection etc. By way of example, in a data plane application there is a packet inspection application in which the data packets are expected to identify malicious data.
Furthermore, a split router architecture is known in which a common router is split into two elements, as known inter alia from a ForCES documentation in IETF at http:datatracker.ietf.org/wg/forces. In this split router architecture a central control entity (CE) is provided responsible for managing the routing protocol and the connectivity of the data plane. The central control entity controls the data plane connectivity through the forwarding elements (FE).
The forwarding element is responsible for forwarding traffic in the data plane, the forwarding element establishing the connectivity to neighbour nodes based on instructions received from the central control entity.
The problem is how to prevent overload of a data plane application in the network. The mechanisms known in the art today are based on the mechanism that the application starts to build up back pressure, when it starts to run out of capacity. In such a situation new incoming data flows are rejected by a data plane application with specific reason codes. Preceding nodes or the data flow source receiving the reason codes can try to find an alternative instance for the targeted application. However, this means that the data flow is first routed to the overloaded application. This routing consumes network capacity. The application then has to reject the data flow, this rejection also requiring capacity from the application, a so-called blind load. The rejection is then routed back again consuming network capacity.
Furthermore, all data flow sources have to implement mechanisms to find alternative instances/alternative network nodes having the same type of application.